Underfloor wiring duct with access opening collar, clamping plate, plug, and adapter



Aug. 8, 1967 J HUDSON ET AL 3,334,457

UNDERFLOOR WIRING DUCT WITH ACCESS OPENING COLLAR, CLAMPING PLATE, PLUG, AND ADAPTER 3 Sheets-Sheet 1 Filed Nov. 20. 1963 INVENTORS Aug. 8, 1967 HUDSON ET AL WIRING DUCT WITH ACCE UNDERFLOOR SS OPENING COLLAR, CLAMPING PLATE PLUG, AND ADAPTER Filed Nov. 20. 1963 3 Sheets-Sheet INVENTORS mMZ Qw t w 3 Sheets-Sheet 3 ND ADAPTER J.W. HUDSON ETAL UNDERFLOOR WIRING DUCT WITH ACCESS OPENING COLLAR, CLAMPING PLATE, PLUG. A Filed Nov. 20. 1963 Aug. 8, 1967 United States Patent 3,334,457 UNDERFLOOR WIRING DUCT WITH ACCESS OPENING COLLAR, CLAMPIN-G PLATE, PLUG, AND ADAPTER James W. Hudson, Harris I. Stanback, and De Forest D. Butler, all of Lexington, Ky., assignors to Square D Company, Park Ridge, 11]., a corporation of Michigan Filed Nov. 20, 1963, Ser. No. 324,924 8 Claims. (Cl. 52221) This invention relates generally to underfloor wiring duct, and more particularly to fittings for the access openings thereof.

A former way of providing access to underfloor wiring duct has been to secure internally threaded cylindrical inserts respectively in round access openings of the duct by rolling or crimping over the inner ends of the cylindrical inserts against the inner surface of the top wall portion of the duct. Most generally this had to be done at the factory, and the duct sections had to be ordered with cylindrical inserts of a depth corresponding to the intended thickness of the concrete floor in which the duct was to be embedded. Further, the inner surfaces of the cylindrical inserts were threaded to provide means for securing service fittings thereto, such internal threading being a relatively expensive operation which it is desirable to eliminate, and because of the threads, the in serts were cylindrical and the access openings were round.

An object of the invention is to provide an underfloor wiring duct having upstanding collar portions defining access openings, the collar portions being drawn to extend a predetermined distance above the top surface of the main portion of the duct to accommodate a concrete floor of predetermined minimum thickness and being adapted to receive extensions securable thereto either at the factory or at the job site to accommodate concrete floors of greater thickness.

Another object is to provide a means whereby extensions are easily securable to drawn upstanding collar portions defining access openings of underfloor wiring duct but are diificult to remove after being installed thereon.

Yet another object is to provide means whereby good electrical contact for grounding purposes may be established between drawn upstanding collar portions defining access openings of underfloor wiring duct and extensions readily securable thereto, even though the duct and extensions are painted before the extensions are secured over the drawn collar portions.

A yet further object is to provide a means for connecting a service fitting to an access opening of an underfloor wiring duct, the means securing the service fitting permitting it to be clamped in any angular position about a vertical axis and accommodating small variations in the thickness of concrete over the duct.

Another object is to provide interchangeable service fitting adapters, stand pipe adapters, and abandoned outlet plugs for drawn upstanding collar portions and collar extensions defining access openings of underfloor wiring duct.

Still another object is to provide an abandoned outlet plug for drawn upstanding collar portions defining access openings, the plug having means for anchoring an abandoned terminal connector in an out-of-the-way position in an underfloor wiring duct shaped to provide storage space adjacent the access opening.

A still further object is to provide a simple and inexpensive means of securing service fitting adapters, stand pipe adapters, and plugs for abandoned outlets in drawn upstanding collar portions and collar extensions defining access openings of underfloor wiring duct.

Other objects and advantages will appear when the following specifications is considered along with the accompanying drawings in which:

FIG. 1 is a fragmentary side elevational view of an underfloor wiring duct constructed in accordance with this invention, the duct being embedded in a concrete floor which is shown in section;

FIG. 2 is an enlarged perspective view of a portion of the duct and floor of FIG. 1, including one of the service fittings secured to the duct;

FIG. 3 is a fragmentary sectional View taken generally along the line 3-3 of FIG. 2;

FIG. 4 is a view similar to FIG. 2, but with the concrete and service fitting omitted;

FIG. 5 is an exploded perspective view of the duct and service fitting of FIG. 2, but additionally including a collar extension for the duct;

FIG. 6 is a view similar to FIG. 3, but with the service fitting replaced by a plug for an abandoned outlet;

FIG. 7 is a perspective view of the structure of FIG. 6, with portions of the duct broken away;

FIG. 8 is an exploded perspective view similar to FIG. 5, but with the service fitting and collar extension replaced by a stand pipe adapter and stand pipe;

FIG. 9 is a fragmentary sectional view of the duct, collar extension, and service fitting of FIG. 5 taken generally along the line 99 of FIG. 10;

FIG. 10 is a a fragmentary sectional view taken generally along the line 10-10 of FIG. 9;

FIG. 11 is an enlargement of a right-hand portion of FIG. 10;

FIG. 12 is a view similar to FIG. 9, but showing the clamping plate for the base of the service fitting inverted from the position thereof in FIG. 9 to accommodate additional thickness of concrete in the floor; and

FIG. 13 is a fragmentary sectional view taken generally along the line 13--13 of FIG. 11.

FIG. 1 shows a length of underfloor wiring duct 20 embedded in a concerete floor 21 and having a plurality of service fittings 22 spaced longitudinally therealong and secured respectively over access openings therein such as the access opening 24 shown in FIG. 4. The service fittings 22 are shown as telephone service outlets, but could just as well be electrical power outlets.

In accordance with the invention, the access openings 24 preferably are elongated longitudinally of the duct 20 and rounded at opposite ends in order that an elongated plug-in type terminal connector 25 on the end of a relatively large cable 27 of limited flexiblity might readily pass through the opening 24 for reception in a service fitting 22.

The duct 20 is specially formed in the vicinity of the access openings 24. Thus, the openings 24 are respectively provided centrally of raised dome portions 29 of the duct. The dome portions 29 are generally diamond-shaped in plan View, the longer dimension of each dome portion extending longitudinally of the duct. Further, each access opening is surrounded by an upstanding collar portion 30 formed integrally with the associated dome portion and is provided on opposite sides with a pair of indentations 32 for a purpose to bedescribed.

The collar portions 30 extend sutficiently above the top surface of the major portion of the duct 20 to accommodate a minimum standard thickness of concrete over the duct. For greater thickness, collar extensions which can 'be readily applied either at the factory or at the job site are provided. One such collar extension 33 is shown in FIGURES 5, 9, and 10. The upper end portion of extension 33 defines an opening of the same size and shape as one of the openings 24 defined by a collar portion 30, while the lower end portion of extension 33 is enlarged to telescope over a collar portion 30 and is provided on op- 3 posite sides with a pair of inwardly extending detents 35 (shown best in FIG. 5) adapted to snap into the indentations 32 in the collar portion 30 to secure the extension 33 thereon. One detent 35 is shown in the righthand portion of FIG. 9, although it is not strictly on the section line 9-9 of FIG. 10.

A plurality of inwardly extending projections 36 (shown best in FIG. 5) is provided on the lower portion of the extension 33 in interfering relationship with the collar portion 30 so as to be sheared off thereby when the extension 33 is telescoped thereover and thus form sharp edges for cutting through paint which may be provided on the duct 20 and establishing a good electrical ground connection between the extension 33 and the collar portion 30. One projection 36 is shown in the left-hand portion of FIG. 9, although it is not strictly on the section line 9--9 of FIG. and although it is sheared off more than indicated upon installation of the collar extension.

For securing a service fitting 22 to the duct, a service fitting adapter 38 (best shown in FIG; 5) having an up standing collar portion 39 is provided and is receivable snugly in either an access opening 24 defined by a collar portion 30 or in the upper end portion of an extension 33. The adapter 38 may be secured in position by a pair of screws 40, which are preferably of the self-tapping type and are inclined, as best shown in FIG. 11, to provide a wedging action for greater holding ability. The adapter 38 is provided with an opposed pair of tapered peripheral recesses 41 for respectively receiving the screws 40, each of which threads paltly into the surface of the adapter 38 defining a recess 41 and partly into the adjacent inner surface of the collar portion 30 or extension 33 to provide a good electrical ground connection in addition to holding the adapter 38 in place. The holes defined by the recesses 41 and the adjacent portions of the collar portion 30 or extension 33 are originally smaller than the diameter of the screws 40. However, the adapter 38 is provided with a pair of generally arcuate yield imparting recesses 37, one of which is best shown in FIGS. 11 and 13. The recesses 37 enable the adapter 38 to bend slightly as the screws 40 are forced into position. Threading the screws into place is thus rendered less difficult, while the natural resiliency of the adapter 38 maintains the screws under compression against the collar portion 30 or extension 33 and the assembly is thus held securely together.

The service fitting 22 includes a base 42 and a cover 44 securable by a plurality of screws 46 (FIGS. 3 and 9) to an opposed pair of upstanding flanges 48 provided on the base 42 and best shown in FIG. 5. The base 42 also includes an opposed pair of upstanding flanges 49 at right angles to the flanges 48, the flanges 49 serving as anchoring plates within the cover 44.

The base 42 is provided with a circular opening 50 for receiving the upstanding collar portion 39 of the adapter 38 and permitting the base to be turned to any angular position with respect to the duct 20. The base is secured to the adapter 38 by means of a generally annular clamping plate 52 having a lip 53 projecting from one side thereof and extending around the inner periphery thereof. The lip 53 defines an opening 54 for receiving the collar portion 39 of the adapter 38. The clamping plate 52 is securable to the adapter 38 by means of a pair of screws 56 :threadable respectively into a pair of holes 58 (FIG. 5) provided in the adapter. Normally the clamping plate is installed with the lip 53 thereof extending upwardly, as shown in FIGS. 9 and 10, but variations in the surface of a concrete floor can be accommodated by installing the clamping plate in an inverted position with the lip 53 extending downwardly, as shown in FIG. 12, and also by varying the amount of overlap between the clamping plate and the collar portion 39 of the adapter.

The service fitting adapter 38 is replaceable by a stand pipe adapter 59 adapted to have a stand pipe 60 secured therein, as shown in FIG. 8, when electrical service outlets are required above floor level.

When an outlet is to be abandoned, a service fitting adapter 38 or a stand pipe adapter 60 may be replaced by a plug 64 for an abandoned outlet, as shown in FIGS. 6 and 7. In such a case, an abandoned terminal connector 25 may be anchored in place by a cotter pin 66 extending through the plug 64 as shown and holding a screw 67 threaded into the terminal connector, thus holding the terminal connector in an out-of-the-way position in the dome portion 29 of the duct 20.

It will be understood that the stand pipe adapters 59 and abandoned outlet plugs 64 are receivable in the collar portions 30 or extensions 33 and-are provided with screw receiving recesses and yield imparting recesses such as the recesses 41 and 37 of the service fitting adapters 38.

It will be seen that a simple means of securing extensions to drawn upstanding collar portions defining access openings in underfloor wiring duct has been provided and that good electrical grounding connections therebetween are insured. Further, a simple means has been provided for securing a service fitting to a collar portion defining an access opening in an underfloor Wiring duct, the securing means permitting the service fitting to be installed at various angles and accommodating variations in the thickness of concrete in which the duct is embedded.

It will further be seen that an abandoned outlet plug has been provided having means for anchoring an abandoned terminal connector in an out-of-the-way position in an underfloor wiring duct having storage space adjacent the access opening in which the plug is installed.

Still further, a simple and inexpensive means of securing service fitting adapters, stand pipe adapters, and abandoned outlet plugs in upstanding collar portions or extensions defining access openings of underfloor wiring duct has been provided.

Various modifications may be made in the structure shown and described without departing from the spirit and scope of the invention.

We claim:

1. An underfloor wiring duct having an upstanding collar portion defining an access opening and means for securing an apertured base portion of a service fitting thereto, said securing means including a service fitting adapter secured in said access opening, and a clamping plate fitted over the end of said adapter remote from said duct and having a portion overlying said base portion and clamping it to said adapter, said clamping plate having a hole therethrough for receiving said end of said adapter and having a lip portion disposed around an inner periphery of the clamping plate defining said hole, said clamping plate being invertible to accommodate variations in the thickness of concrete in which said duct may be embedded, and said lip portion extending through said base portion in a position of the clamping plate in which said lip portion extends toward said duct from the remainder of said clamping plate.

2. An underfloor wiring duct having an upstanding collar portion defining an access opening and securing means for securing an apertured base portion of a service fitting thereto, said securing means including a service fitting adapter, a pair of screws securing said adapter in said access opening, said screws being respectively dis posed on opposite sides of said adapter and each screw including a threaded shank portion disposed between said upstanding collar portion and said adapter, whereby the threads of the screw engage said upstanding collar portion along one part of their periphery and engage said adapter along another part of their periphery, and an apertured clamping plate fitted over the end of said adapter remote from said duct and having a portion overlying said base portion and clamping it to said adapter.

3. A duct and securing means as claimed in claim 2, wherein said screws are inclined to provide a wedging effect to prevent said adapter from being pulled out of said access opening.

4. A duct and securing means as claimed in claim 2, wherein said adapter is provided with a pair of yield imparting recesses respectively adjacent said screws enabling said screws to be more easily threaded between said adapter and upstanding collar portion.

5. A duct and securing means as claimed in claim 2, including a second pair of screws securing said clamping plate to said adapter, said second pair of screws being respectively disposed on opposite sides of said adapter and each screw including a threaded shank portion disposed between said upstanding collar portion and said adapter, whereby the threads of the screw engage said upstanding collar portion along one part of their periphery and engage said adapter along another part of their periphery.

6. An abandoned outlet plug, an upstanding collar portion defining an access opening of an underfloor wiring duct, said plug being secured in said access opening by a pair of screws respectively disposed on opposite sides of said plug with threaded shank portions of the screws disposed between said plug and said upstanding collar portion and the threads of the screws engaging said plug along one part of their periphery and engaging said upstanding collar portion along another part of their periphery, and said plug having a pair of yield imparting recesses respectively adacent said screws enabling said plug to yield upon the threading of said screws between said plug and said upstanding collar portion.

7. An abandoned outlet plug as claimed in claim 6, including means for anchoring an abandoned terminal connector thereto.

8. A stand pipe adapter for an upstanding collar portion defining an access opening of an underfloor wiring duct, said stand pipe adapter being securable in said access opening by a pair of screws respectively disposed on opposite sides of said stand pipe adapter with threaded shank portions of the screws disposed between said stand pipe adapter and said upstanding collar portion and the threads of the screws engaging said stand pipe adapter along one part of their periphery and engaging said upstanding collar portion along another part of their periphery, and said stand pipe adapter having a pair of yield imparting recesses respectively adjacent said screws enabling said stand pipe adapter to yield upon the threading of said screws between said stand pipe adapter and said upstanding collar portion.

References Cited UNITED STATES PATENTS 910,261 1/ 1909 Ames et al 220-37 1,692,097 11/ 1928 Staples 220- 1,820,824 8/ 1931 Phifler 220-37 1,824,571 9/1931 Richardson 52-221 1,977,891 10/1934 Olley -57 2,063,569 12/ 1936 Walker 52-221 2,291,706 8/1942 Frease 285-189 2,316,166 4/ 1943 Huguelet 174-78 2,808,825 10/ 1957 Solomon 285-189 3,047,650 7/1962 Reiland 52-221 3,170,029 2/ 1965 Stewart 220-38 FOREIGN PATENTS 632,756 12/ 1949 Great Britain.

FRANK L. ABBOTT, Primary Examiner. J. L. RI DGILL, Assistant Examiner. 

1. AN UNDERFLOOR WIRING DUCT HAVING AN UPSTANDING COLLAR PORTION DEFINING AN ACCESS OPENING AND MEANS FOR SECURING AN APERTURED BASE PORTION OF SERVICE FITTING THERETO, SAID SECURING MEANS INCLUDING A SERVICE FITTING ADAPTER SECURED IN SAID ACCESS OPENING, AND A CLAMPING PLATE FITTED OVER THE END OF SAID ADAPTER REMOTE FROM SAID DUCT AND HAVING A PORTION OVERLYING SAID BASE PORTION AND CLAMPING IT TO SAID ADAPTED, SAID CLAMPING PLATE HAVING A HOLE THERETHROUGH FOR RECEIVING SAID END OF SAID ADAPTER AND HAVING A LIP PORTION DISPOSED AROUND AN INNER PERIPHERY OF THE CLAMPING PLATE DEFINING SAID HOLE, SAID CLAMPING PLATE BEING INVERTIBLE TO ACCOMMODATE VARIATIONS IN THE THICKNESS OF CONCRETE IN WHICH SAID DUCT MAY BE EMBEDDED, AND SAID LIP PORTION EXTENDING THROUGH SAID BASE PORTION IN POSITION OF THE CLAMPING PLATE IN WHICH SAID LIP PORTION EXTENDS TOWARD SAID DUCT FROM THE REMAINDER OF SAID CLAMPING PLATE. 